linux-kernel - [tip:perf/urgent] perf top: Display the LBR stats in callchain entry

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Date:   Tue, 6 Nov 2018 11:14:37 -0800
From:   tip-bot for Jin Yao <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     jolsa@...nel.org, linux-kernel@...r.kernel.org, acme@...hat.com,
        hpa@...or.com, kan.liang@...ux.intel.com, ak@...ux.intel.com,
        peterz@...radead.org, alexander.shishkin@...ux.intel.com,
        yao.jin@...ux.intel.com, mingo@...nel.org, tglx@...utronix.de
Subject: [tip:perf/urgent] perf top: Display the LBR stats in callchain
 entry

Commit-ID:  590ac60d8aa929bd21e35cd95a7d8720d00eb4f3
Gitweb:     https://git.kernel.org/tip/590ac60d8aa929bd21e35cd95a7d8720d00eb4f3
Author:     Jin Yao <yao.jin@...ux.intel.com>
AuthorDate: Wed, 31 Oct 2018 19:06:35 +0800
Committer:  Arnaldo Carvalho de Melo <acme@...hat.com>
CommitDate: Mon, 5 Nov 2018 14:37:11 -0300

perf top: Display the LBR stats in callchain entry

'perf report' has supported the displaying of LBR stats (such as cycles,
predicted%) in callchain entry.

For example:

  $ perf report --branch-history --stdio

  --1.01%--intel_idle mwait.h:29
            intel_idle cpufeature.h:164 (cycles:5)
            intel_idle cpufeature.h:164 (predicted:76.4%)
            intel_idle mwait.h:102 (cycles:41)
            intel_idle current.h:15

While 'perf top' doesn't support that.

For example:

  $ perf top -a -b --call-graph branch

  -   13.86%     0.23%  [kernel]		[k] __x86_indirect_thunk_rax
     - 13.65% __x86_indirect_thunk_rax
        + 1.69% do_syscall_64
        + 1.68% do_select
        + 1.41% ktime_get
        + 0.70% __schedule
        + 0.62% do_sys_poll
          0.58% __x86_indirect_thunk_rax

Actually it's very easy to enable this feature in 'perf top'.

With this patch, the result is:

  $ perf top -a -b --call-graph branch

  $ -   13.58%     0.00%  [kernel]		[k] __x86_indirect_thunk_rax
     $ - 13.57% __x86_indirect_thunk_rax (predicted:93.9%)
        $ + 1.78% do_select (cycles:2)
        $ + 1.68% perf_pmu_disable.part.99 (cycles:1)
        $ + 1.45% ___sys_recvmsg (cycles:25)
        $ + 0.81% unix_stream_sendmsg (cycles:18)
        $ + 0.80% ktime_get (cycles:400)
          $ 0.58% pick_next_task_fair (cycles:47)
        $ + 0.56% i915_request_retire (cycles:2)
        $ + 0.52% do_sys_poll (cycles:4)

Signed-off-by: Jin Yao <yao.jin@...ux.intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@...hat.com>
Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc: Andi Kleen <ak@...ux.intel.com>
Cc: Jiri Olsa <jolsa@...nel.org>
Cc: Kan Liang <kan.liang@...ux.intel.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Link: http://lkml.kernel.org/r/1540983995-20462-1-git-send-email-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 tools/perf/builtin-top.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index b2838de13de0..aa0c73e57924 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -1429,6 +1429,9 @@ int cmd_top(int argc, const char **argv)
 		}
 	}
 
+	if (opts->branch_stack && callchain_param.enabled)
+		symbol_conf.show_branchflag_count = true;
+
 	sort__mode = SORT_MODE__TOP;
 	/* display thread wants entries to be collapsed in a different tree */
 	perf_hpp_list.need_collapse = 1;